The history of the nebulize has been well documented. The nebulizer is a pneumatic, or electric powered device that nebulizes medications, at a particulate droplet size, to be delivered through an opening in the top of the nebulizer into a "T" which is attached at each end into the ventilator circuit. The medication is then mixed and delivered through the ventilator tubing, or circuit, into the interior airways of the patient. The particle size of the delivered medication is important and should be of correct size for better distribution throughout the airways. If the particles (droplets) of medication are too large they will be delivered to the interior of the trachea and upper airways. If the particulate droplets are too small they will be exhaled. If the correct size droplets are distributed throughout the bronchial tree, the patient will be benefitted.
Many different nebulizers, commonly called hand held nebulizers, are commercially available. They hold up to 10cc's of medication. They include an elongated body three and one half inches long and are used in a vertical position. An unvalved "T" is attached to the top of the nebulizer which can be coupled into the ventilator circuit. The source gas entry tubing is vertically inserted into the bottom of the nebulizer. The device from the top of the "T" to the bottom of the source gas connector may be up to 6 inches in height. Such nebulizers are used in ventilator circuits and medication added by unscrewing the cap from the bowl and injecting the medication into the bowl, or by removing the "T" from the top of the nebulizer body and injecting the medications into the bowl. The cap or "T" is then replaced on the nebulizer. The ventilator circuit is then disconnected proximal to the patient on the inspiratory side of the circuit. The nebulizer is placed into the circuit by connecting the disconnected tubing of the circuit to the end of the "T" , and the other end of the "T" is attached to a six inch piece of tubing that is then attached proximal to the patient at a patient "Y". The nebulizer is then started and the medications are nebulized and delivered through the top of the nebulizer into the ventilator circuit. The medication in small particle size droplets is picked up by the gas of the inspiratory phase of the ventilator cycle and delivered into the airways.
Drawbacks of the commercially available nebulizers are that most are designed to be used in a vertical position or slightly tilted from vertical position in the ventilator circuit. When this position is not maintained all of the medication is not nebulized. A portion of the medication remains in the nebulizer bowl. Further, the source gas tubing entering the bottom of the nebulizer vertically often kinks off due to the weight of the circuit structure pushing down on the nebulizer, which nebulizer often rests on the patient's chest or shoulder. When the tubing of the source gas kinks off, the gas flow is reduced. Poor or no nebulization of the medication results. Further, the height of the device, when inline, in the ventilator circuit makes it hard to place the nebulizer proximal to the patient. With a six inch piece of tubing placed between the nebulizer and the patient, the six inches of extra tubing creates rainout of medication into the tubing. A portion of the medication never reaches the interior of the airways and is of no benefit.
A further drawback is that each time the patient needs medication nebulized, the ventilator circuit is disconnected from the patient. The nebulizer is placed in line and the ventilator circuit reconnected. Medication is nebulized. The nebulizer is thereafter taken out of the circuit and the circuit is then, again reconnected. The nebulizer is put away until its next use.
Patients receive medications in this manner from 4 to 24 times each day. Each time the ventilator circuit is disconnected depressurization occurs which compromises the oxygen blood levels of the patient who is being supported with positive end expiratory pressure (PEEP). PEEP is pressure constantly used in the circuit to keep the alveoli open for gas exchange to occur in the terminal airways of the patient's lungs. Further, each time the circuit is opened to the atmosphere to place the nebulizer inline, or to remove it, contamination of the ventilator circuit and the nebulizer can occur.
A further drawback is that if the nebulizer is left in the circuit it will fill with water from condensation in the tubing and the water would have to be drained therefor before the nebulizer could be used.
A further drawback during emergencies is that when patients are being ventilated with a resuscitation bag, cardiac medications are delivered via the intubation tube into the lungs for faster effect to the heart. Currently nebulizers with "T"s are too cumbersome to nebulize heart medications during resuscitation.
A further drawback exists. In recent years the use of continuous nebulized medication has been found to be beneficial in treating some patients with lung disease. Currently most nebulizers have to be adapted to permit their use for continuous nebulization as they do not have a medication port that can be connected to IV tubing.